ARM IV: Patients receive the same treatment as in arm I for 1 month. Beginning within 7-21 days after completion of chemotherapy, patients undergo radiotherapy (3-dimensional conformal radiotherapy or intensity-modulated radiotherapy) 5 days per week for 5.5 weeks (28 fractions). During radiotherapy, patients receive either capecitabine PO twice daily (BID) 5 days per week or fluorouracil IV continuously for 5.5 weeks or until radiotherapy is completed.